Centrifugal device for dehydrating a fine-granular material



J 27, 1959 w. G. J. HECKMANN 2,870,913

CENTRIFUGAL DEVICE FOR DEHYDRATING A FINE-GRANULAR MATERIAL Filed Oct.27. 1954 5 Sheets-Sheet 1 Jan. 27,1959 w. G. J. HECKMANN 2,870,913 FORDEHYDRATING A FINE-GRANULAR MATERIAL CENTRIFUGAL DEVICE 3 Sheets-Sheet 2Filed Oct. 27. 1954 Jan. 27, 1959 wics. J. HECKMANN 2,

CENTRIFUGAL DEVICE FOR DEHYDRATING A FINE-GRANULAR MATERIAL 5Sheets-Sheet 6 Filed Oct. 27. 1954 Fig.3

' INVENTO; I B/ W CENTRIFUGAL DEVICE FOR DEHYDRATING A FINE-GRANULARMATERIAL Wolfgang Gertrud Joseph Heckmann, Koln-Deutz, Germany, assignorto Klt'ickner-Humboldt-Deutz Aktiengesellschaft, Koln, Germany, acorporation of Germany The present invention relates toa centrifugaldevice for dehydrating a material, and more particularly to a centrifugefor dehydrating a sludge or slurry, such as a slurry consisting of coalparticles.

It is an object of the present inventionto render simple theconstruction of a centrifugal device of the kind described.

It is another object of the present invention to provide a centrifugaldevice having driving members which are easily accessible.

Other objects and advantages of the present invention will becomeapparent from the following detailed description thereof when read inconnection with the ac companying drawings showing, by way of example,an embodiment of the present invention. In the drawings Fig. 1 is anelevation, partly in section, of a first embodiment of the presentinvention,

Fig. 2 s a plan view of the device shown in Fig. 1,

Fig. 3 is a cross-section taken along the line E-F of Fig. 1,

Fig. 4 shows a detail of Fig. 1 on an enlarged scale.

Referring now to the drawings, the centrifugal device is provided with asieve drum 1 open at the upper end thereof and having a bottom plate 2.The sieve drum 1 includes a conical sieve portion 3 provided withperforations having a diameter of approximately 0.15 mm. The conicalsieve portion 3 is inclined relative to the axis CD of the drum by anangle of 10 to 15. Preferably the sieve drum 1 is provided .at the upperrim thereof with a flangef37 projecting towards the outside. The meandiameter of the sieve drum 1, i. e. the diameter at half the heightthereof amounts, for example, to 400 mm. To the bottom plate 2 isattached by means of a fiange 65 a central shaft projectingv upwardsbeyond the sieve drum 1 and comprising the two preferably hollow shaftportions 4 and 4a screwed to one another by means of flanges 30 and 30bbetween which an inner projection 32a of a pulley 32 isarranged. Theparts 30, 31 and 32 are connected by screws 30a. The upper shaft portion4a is supported rotatably about the axis thereof by roller bearings 5and 6 which abut against a casing or housing 7 so that the shaft portion4a cannot move axially with respect to the casing or housing 7. Thebearings 5 and 6 are adjustable by means of a look hot 8 arranged on theupper end of the shaft 4a and fastened by means of a screw 9. Thehousing or casing 7 is provided at the lower edge thereof with a flange10 (Fig. 3) preferably having three aims and is secured against thepenetration of dirt and moisture by means of a disc 38 carrying apacking 39. The flange 10 is clamped at three points uniformly spacedabout said shaft between rubber springs 11 and 12. The rubber springs 11abut with the lower face thereof against a plate 13 secured by means ofscrews to the cylindrical outer wall 14 of the frame of the centrifugegenerally denoted by 80. The plate 13 is provided with an aperture 66through which the shaft 4 may be introduced from. above; The upper endfaces of United States Patent 1 O the rubber springs 12 abut against acover 16 of a box- Y shaped member 17 open at the lower side thereof andenclosing the springs 11, 12. The box 17 is, asshown in Fig. 3,preferably formed with three arms 18, 19 and 20 providing ample spacefor receiving the rubber springs 11, 12 and the flange 10. Whereas thearms 18 and 19 are relatively short, the arm 20, reinforced by atransversal rib 51, is lengthened toward the outside so as to extendbeyond the outer wall 14 of the frame 80. The enclosing wall 17a of thebox 17 is provided at the lower edge thereof with lugs 21 and 22directed. to the outside and forming members connecting the box 17 withthe plate 13. The height of the enclosing wall 17a is chosen so that therubber springs 11, 12 are slightly compressed when the box 17 is screwedto the plate 13 so as to prestress the rubber springs 11, 12. Theprestressing may be increased or regulated by inserting plates, such as12a, for instance, between the flange 10 and the springs 11, 12.Preferably the springs 11, 12 are provided with an axial boring 25, thecover 16, the flange 11], and the plate 13 being provided with plugs 26and 27 protruding some what into the bore 25. By this arrangement it isachieved that the springs 11, 12 retain the correct positions thereofduring the assembling of the device. Furthermore, as will be seen fromFigs. 2 and 3, the plate 13 is provided inside the gaps separating thearms 18, 19 and 20 with sector-shaped recesses 23 so that the sieve drum1 is accessible through the same and may be easily. watched inoperation.

The pulley 32 is connected by means of three V-belts 33 with a motor 34attached to the wall 14. The V- belts 33 are arranged within the arm 20of the box 17, the arm 20 having a widthsufl icient for accommodatingthe V-belts 33. Preferably, the outer end of the arm 20,

is provided with a cap 35 embracing the drive pulley 36 connected to themotor 34. The cap 35 forms the closure member of the arm 20 toward theoutside so that the V- belt drive 36, 33, 32 is protected against dustand dirt.

Within the arm 20, and more particularly in the middle with the flange10. The torsion spring 31 has a diame ter suificient to take up the beltpull of the drive 36, 33, 32. In this manner, the shaft 4, 4a cannot bedisplaced toward the left under the action of the pull of the V-belts.

The casing 7 is rigidly connected to a frame 42 which forms the uppercover of the casing 7 so that the inner I part of the same is protectedalso against the penetration of dirt and moisture from above. A shaft 44arranged in parallel to the plane of symmetry H] is arranged forrotation in the frame 42 by means of roller bearings 43. The shaft 44projects at both ends beyond the frame 42 and carries two discs 45, 46being provided, respectively with eccentrically arranged weights 47, 47.The shaft 44 is connected with a second motor 50 arranged on and abovethe arm 20 by means of two resilient coupling members 70, 71 shown on anenlarged scale in Fig. 4, and an intermediate shaft 76. The couplingmembers 70, 71 each include a resilient member or rim 74 beingarc-shaped in cross-section and consisting,

for instance, of rubber, the rim 74 by means of rings. 75, 75a and screwbolts 76, 77 connecting the clutch; halves 72 and 73 arranged at adistance from each other.,, Thus the coupling members 70, 71 areresilient in the,

axial direction thereof owing to the resilient rim 74, and are movabletransversely in all directions in the manner of a universal joint.

A centrally arranged tube or pipe 51 is connected to the lower side ofthe plate 13 symmetrically to the aperture 6,6, the tube or pipe 51terminating at a small distance above the bottom plate 2 of the sievedrum 1. Aninclmed tube or pipe 52 opens laterally into the tube or pipe51, the tube or pipe 52 being connected at its upper end with a feedpipe (not shown) for the material to be centrifuged. The sieve drum 1 issurrounded by an annular wall 53 preferably shaped in the upper partthereof as a cone. Ribs 54 secure the lower part of the annular wall 53to the outer wall 14. The annular wall 53 is closed at the lower endthereof by a bottom 55 so as to form a container 56 collecting the waterseparated from the material to be centrifuged. Immediately above thebottom 55 two pipes 57 and 5.8 open into the contamer at oppositeplaces, the pipes 57 and 58 withdrawng the separated water from thecontainer 56. The wall 53 extends upwards so that its upper edge isseparated from the lower side of the flange 37 so as to define a gaptherebetween. Preferably the wall 53 is provided at the inner sidethereof with a hollow cylindrical ring 59 directed downwards,Furthermore, it is advisable to arrange on the flange 37 a hollowconical ring 60 extendmg parallel to the conical part of the wall 53 andhaving a lower edge arranged below the ring 59. Preferably a hollowconical ring 62 is provided within the container 56 formed by the wall53. The conical ring 62 is attached by means of ribs 63 to the wall 53and extends parallel to the ring 60 so as to project with the upper edgeportion thereof into the gap between the conical sieve portion 3 and thering 60. The lower edge of the ring 62 is arranged at a distance fromand above the bottom 55. The annular space 61 between the walls 53 and14 opens towards the lower side thereof into a collecting bunker 65 onwhich the centrifuge is mounted, preferably on rubber springs 66.Preferably a hollow cylinder 64 consisting of rubber or similarresilient material is arranged on the inside of the upper end of theWall 14 and at a distance therefrom, the cylinder 64 extending downwardso far that its lower rim is arranged below the level of flange 37.

The operation of this device is as follows:

The shaft 4, 4a and the sieve drum 1 rigidly connected thereto arerotated by the motor 34 by means of the belt drive 36, 33 and 32 at, forinstance, 1400 revolutions per minute. At this speed of revolutions acentrifugal acceleration raw of approximately 400 times the accelerationof gravity prevails at half the height of the drum 1, that is where thesame has a diameter of 400 mm. At the same time, the discs 45 and 46,with the eccentrically arranged weights 47, 47' are rotated by the motor50 connected with the discs 45, 46 by the coupling members 70, 71 andthe intermediate shaft 76. On an average about 30v cubic meters per hourof concentrated coarse coal slurry containing about 600 grams of coalper liter, having a particle size below and including 1 mm. diameter,are supplied to the sieve drum 1 by the tubes or pipes 52 and 51. Theslurry, after its exit from the tube 51 hits the bottom 2 of the sievedrum 1 from where it is transported by the action of the centrifugalforce to the conical sieve portion 3, a large portion of the watercontained in the slurry being discharged through the openings in sieveportion 3.

The torsion spring 31 is flexible in all directions and furthermore,permits a twisting of the casing 7 about the longitudinal axis thereof.In consequence thereof, the casing 7 may rotate within certain limitsabout the point G, being the intersection of the axis of the torsionspring 31, with the axis C-D, the rotation being effected as it were inthe manner of a universal joint. By this, the shaft 4, 4a is enabled tocarry out precession move ments about the fixed point G if an unbalanceis produced 4 within the sieve drum 1, for instance, owing to nonuniformdistribution of the material.

The center of gravity S of the system suspended from the springs 11, 12is very low owing to the large mass of the sieve drum 1--3 and of thecontents thereof. In consequence thereof, the shaft 4, 4a which isinfluenced by substantially horizontal centrifugal components caused bythe rotating weights 47, carries out a pendulum movement about the pointS. The casing 7 may follow these movements since the torsion spring 31is flexible in all directions. The pendulum movement carried out by thesieve drum 1-3 is so small owing to the short distance of the center ofgravity S from the bottom 2 of the sieve drum 1 that it is practicallynegligible. The vertical 5 components of the centrifugal forces exertedby the weights 47 impart vertical vibrations having an amplitude ofabout 1.5 to 3 mm. to the shaft 4, 4a and'to the sieve drum 1'.-.3carried by the same. The drive for the vibrational movements ispreferably operated at hypercritical speeds, that is far above thenatural frequency of vibration, for instance, at a frequency of 50cycles per second. Under the action of the vibrating movement, the coaltravels as a layer of about 10 mm. thickness on the sieve drum 3 towardsthe upper rim 37 thereof, the coal being further dehydrated thereby. Thedehydrated coal finally leaves the sieve drum 3 over the flange 37 fromwhence it is thrown against the rubber ring 64 preventing the coal fromhitting the wall 14. Thus further disintegration by a bounding effect,particularly of the coarser coal particles is prevented by the rubberwall 64. The coal dropping from the wall 64 passes through the annularspace 61 into the collecting bunker 65. The water passing through theconical sieve portion 3 hits the conical rings 62 and 60 and isdeflected by the same toward the bottom 55. Sprayed water particleswhich might be deflected toward the top are caught by the cylindricalring 59. Thus, the rings 62, 60 and 59 practically prevent the waterfrom passing from the container 56 into the annular space 61. The watercollecting in the container 56 is discharged through the pipes 57 and58.

I have described a preferred embodiment of my invention, but it shouldbe understood that this disclosure is only for the purpose ofillustration and that various omissions or changes in shape, proportionand arrangement of parts, as well as the substitution of equivalentelements for those herein shown and described, may be made withoutdeparting from the spirit and scope of the invention set forth in theappended claims.

I claim:

1. A centrifugal device for dehydrating a fine-granular materialcomprising, in combination: a frame, a casing .resiliently mounted onsaid frame for performance of vibrating movements substantially in thedirection of its longitudinal axis, a first shaft, a first portion ofsaid shaft being rotatably and axially immovably arranged in said;casing, a second portion of said shaft projecting from said casing, asieve drum surrounding at least a part of said second portion of saidshaft and being rigidly connected therewith, driving means for rotatingsaid shaft, and vibrating means for imparting vibrations to said casingwhereby said sieve drum is subjected to vibrating movements in additionto its rotating movements.

2. In a centrifugal device as claimed in claim 1, said sieve drum havingan open end, and one end of said shaft extending beyond said open end ofsaid sieve drum.

3. In a centrifugal device as claimed in claim 1 said driving meansincluding a motor and means operatively connecting same with said shaft,said motor being mounted on said frame.

4. A centrifugal device as claimed in claim 1, said casing and saidfirst shaft being coaxial with one another.

5. A centrifugal device as claimed inclaim 4, including a flange fixedlyattached to said casing, and resilient means for clamping said flangeto. said frame.

6. A centrifugal device as claimed in claim 5, said resilient meansincluding rubber springs.

7. A centrifugal device as claimed in claim 6, said rubber springs beingarranged in pairs, said flange being clamped between said pairs ofsprings.

8. A centrifugal device as claimed in claim 7, said rubber springs beingarranged in a plurality of positions uniformly spaced on said flangeabout said first shaft.

9. A centrifugal device as claimed in claim 8, including a second shaftrotatably arranged on said casing at an angle to said first shaft, drivemeans for rotating said second shaft, and vibrating means responsive torotation of said second shaft to impart axial vibrations to said casing.

10. A centrifugal device as claimed in claim 9, including at least oneweight arranged eccentrically on said second shaft for imparting to thesame vibrations in the transversal direction thereof, and means fortransmitting said axial vibrations to said casing.

11. A centrifugal device as claimed in claim 9, includinga belt drivefor rotating said shaft about the axis thereof, said belt drive having aplane of symmetry, and said axis being arranged in said plane ofsymmetry of said belt drive.

12. A centrifugal device as claimed in claim 11, including a resilientmember connecting said casing with said frame, said resilient memberbeing arranged in said line of symmetry of said belt drive.

13. A centrifugal device as claimed in claim 12, said resilient memberbeing a resilient bar the respective ends thereof being fastened to saidflange and to said frame.

14. A centrifugal device for dehydrating a fine-granular materialcomprising, in combination: a frame, a casing resiliently mounted onsaid frame for performance of vibrating movements substantially in thedirection of its longitudinal axis, a shaft, a first portion of saidshaft being rotatably and axially immovably arranged in said casing, asecond portion of said shaft projecting from said casing, a sieve drumsurrounding at least a part of said second portion of said shaft andbeing rigidly connected therewith, means for rotating said shaft, asecond shaft arranged on said casing at an angle to said shaft, meansfor rotating said second shaft, coupling means including resilient partsfor coupling said second shaft with said means for rotating the same,and at least one weight arranged eccentrically on said second shaft andimparting to the same vibrations in the transversal direction thereof,said transversal vibrations imparting axial vibrations to said casingwhereby said sieve drum is subjected to vibrating movements in additionto its rotating movements.

References Cited in the file of this patent UNITED STATES PATENTS275,874 Weston Apr. 17, 1883 2,254,455 Sorenson Sept. 2, 1941 2,361,767Hays Oct. 31, 1944 2,494,584 Rouse Jan. 17, 1950

